The scene in Digbeth

A shop worker at the Custard Factory saw one of the men as he crouched down to be sick.

The eyewitness, who did not want to be named, said: “One guy looked practically dead. He was not in a good state at all. We quite often get businesses dropping off ‘party menus’ with a list of legal highs and the effects they have.

“We always say ‘no thanks’ and ask them to take the menus away.”

Police had temporarily closed Heath Mill Lane, between Digbeth High Street and Lower Trinity Street, to allow paramedics to treat the patients and for officers to conduct enquiries.

A spokesman said: “Enquiries suggest the three individuals were suffering the effects of ingesting a legal substance.”

But by this evening police said they were no longer investigating.

Picture by Michael Scott (Image: Picture by Michael Scott)

Earlier this year, a Birmingham MP called for controls over ‘legal highs’ on the internet, after it emerged more than 280 synthetic drugs are being sold across Europe.

Steve McCabe (Lab, Selly Oak), a member of the Home Affairs Select Committee, said: ‘‘The difficulty with these products is that it is hard simply to make them illegal because the manufacturers can make changes to the product and effectively create a new substance which isn’t covered by the law but has the same effect.

“Often they are sold over the internet and we need to look at ways of regulating and controlling that better. It’s not easy to do and it requires international co-operation, but we need to get a grip on online sales just as we would with the sale of firearms. Some of these substances are genuinely dangerous.”